This paper describes the development of Mörri, a multi purpose robot platform. The design of this robot includes mechanical, electrical and software development. Key features of the robot are modularity for multi-purpose applications, affordable size for outdoor and indoor operation, low cost, high performance, and easy to use and repair in field conditions. The main focus on software architecture development has been on creating fully-functional real-time architecture, where several algorithms and methods can be easily integrated as part of the system. As a result, this robot took part on M-Elrob outdoor robot competition in July 2008 and won "Camp Security" scenario.